I haven’t had much time to spend on the bus recently but did get back to it yesterday and today.   Some new tools arrived today, a set of diamond-tipped hole cutters  and a very small plug cutter and these have made it much easier to extract broken screws and nails.  I made good progress today in removing said broken screws etc along the nearside framing at waist level and in the side rods and window pillars, the new tools making the job much quicker than hitherto.  I should be able to finish repairing and painting the frame soon though there is still the metalwork to be made and fitted and the bottom of the side rods and the bottom rails need to be cut.